Place the steak strips in a bowl and add the egg. Mix together to thoroughly coat the steak in the egg.

Add the cornflour, salt, pepper, and white pepper.

Toss together to coat the steak. It will be a sticky mixture.

Heat 3 tablespoon of the oil in a large frying pan (skillet) or wok over a high heat until very hot.

Add in half the beef, a strip at a time, and spread it out.

Fry the steak until dark brown and crispy, taking about 5 or 6 minutes with 3 or 4 stirs during that time.

Using a slotted spoon or tongs, remove the beef from the pan and place in a bowl lined with kitchen roll to soak up excess fat.

Add a further tablespoon of oil and repeat - cooking the second batch of beef and placing in the bowl with the first batch.

Add the remaining ½ tablespoon of oil to the pan, turn the heat down to medium, and add in the sliced onion. Cook for 2 minutes until slightly softened.

Add in the finely chopped chilli, minced ginger, and minced cloves of garlic and cook whilst stirring for 30 seconds.

Add the rice vinegar, soy sauce, tomato puree, sugar, tomato ketchup, and sweet chilli sauce to the pan.

Turn up the heat and let it bubble for a couple of minutes until the sauce starts to reduce a little.

Add the beef back in, give it a stir and heat through for 1-2 minutes until the beef is hot.

Serve with rice or noodles.